# Seeing An Atom? What's the SD? **URL:** \ **Category:** Factual Questions\ **Created:** [February 15, 2018, 3:47pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877 "2018-02-15T15:47:57Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [February 15, 2018, 3:47pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/1 "2018-02-15T15:47:57Z")
According to [this BGR.com article](http://bgr.com/2018/02/14/single-atom-photo-strontium-picture-image/) (also carried by [Yahoo.com](http://Yahoo.com)), a photographer allegedly photographed a Strontium atom held in suspended animation between two electrodes supposedly exciting the atom causing it to glow. if you blow up this picture, you can see a speck of something, but I seriously doubt it is ONE atom. The article lacks explanation how we can see an image of one atom - even if it is emitting light by being excited by lasers. Note: The scale of the of smallest thing we can see, visible light, is in the realm of nanometers (1x10^-9 meters) vs. the scale of the size of the Strontium atom is in the realm of picometers (1x10^-12 meters). That means the atom is in the ballpark of 1,000 times smaller than what the minimum the human eye can detect. Sure, we see the manifestation of excited atoms all the time. But, seeing one atom au naturale? What’s the whole story here, Straight Dopers? ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [February 15, 2018, 3:53pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/2 "2018-02-15T15:53:27Z")
The photograph is magnified substantially. The distance between the electrodes is actually 2 mm according to [this](https://www.epsrc.ac.uk/newsevents/news/single-trapped-atom-captures-science-photography-competitions-top-prize/). In other words, the equipment looks like it’s “actual size” but it isn’t, and the atom isn’t actual size either. You’re also not actually seeing the atom; you are seeing refraction of a laser from the atom. ---
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [February 15, 2018, 4:12pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/3 "2018-02-15T16:12:03Z")
> [@Really\_Not\_All\_That\_Bright](#): > > The photograph is magnified substantially. The distance between the electrodes is actually 2 mm according to [this](https://www.epsrc.ac.uk/newsevents/news/single-trapped-atom-captures-science-photography-competitions-top-prize/). In other words, the equipment looks like it’s “actual size” but it isn’t, and the atom isn’t actual size either. You’re also not actually seeing the atom; you are seeing refraction of a laser from the atom. To be clear, when you say “refraction of a laser”, you mean we’re seeing the deflection of a laser beam due to the presence of the atom. So, it could be said we are seeing a hole in the laser beam created by this deflection…magnified for the camera to record. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [February 15, 2018, 4:14pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/4 "2018-02-15T16:14:34Z")
Perfect response and explanation in this thread: [https://boards.straightdope.com/sdmb/showpost.php?p=20784229&postcount=7](https://boards.straightdope.com/sdmb/showpost.php?p=20784229&postcount=7) ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [February 15, 2018, 4:16pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/5 "2018-02-15T16:16:26Z")
> [@Really\_Not\_All\_That\_Bright](#): > > You’re also not actually seeing the atom; you are seeing refraction of a laser from the atom. By this standard, you’re _never_ seeing atoms, just light reflecting off (or refracting through, or similar) atoms. This is an atom in an ion trap which is re-transmitting light shone onto it by a laser. It _is_ a single atom, and it _is_ re-transmitting visible light. Saying you’re seeing light and not an atom is a few shades too pedantic for experts to credit. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [February 15, 2018, 4:36pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/6 "2018-02-15T16:36:59Z")
Sure. But the point is you wouldn’t be able to see it without the laser. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [February 15, 2018, 6:15pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/7 "2018-02-15T18:15:47Z")
> [@Really\_Not\_All\_That\_Bright](#): > > Sure. But the point is you wouldn’t be able to see it without the laser. Isn’t that true for everything we see ? You either need external light to be reflected/refracted or energize something to radiate light . ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [February 15, 2018, 7:01pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/8 "2018-02-15T19:01:31Z")
You know how when you look at a really bright light source, the ‘glow’ is much bigger than the bulb itself? I think that’s what is happening here. I mean, that dot is still _way_ larger than the atom itself. It’s just that the atom is being energized strongly and it’s emitting a ton of photons, and you’re seeing those photons. You can take images of atoms indirectly, through measuring the electric potential of their electron clouds with high end microscopes. This results in an image where you can in fact “see” the molecules correctly down to the individual atoms on the surface. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [February 15, 2018, 7:51pm UTC](https://boards.straightdope.com/t/seeing-an-atom-whats-the-sd/808877/9 "2018-02-15T19:51:43Z")
What percentage of our vision does the physical mass of a distant star inhabit?